Grab-hook.



0. BJHARP;

GRAB HOOK.

APPLICATION FILED DEG.19, 1912 Patented Jan. 6, 1914.

11209125571 i'' z ZZZ) I uy/Aha lilvll a, L; (QM/ M COLUMBIA PLANOGRAPH 470., WASHINGTON, D. c.

CHARLES B. HARP, or LOS memes, CALIFORNIA.

GRAB-HOOK.

Specification of lletters Patent.

Patented Jan. 6, 1914.

Application filed December 19, 1912. Serial No; 737,746.

To all whom it-may concern:

Be it known that 1, CHARLES E; HARP, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented a new and useful Grab-Hook, of which the following is a specification.

This invention relates to a grab hook designed for lifting building material such, for example, as concrete slabs, by grlpping the same on opposite side faces so that the lower face of the slab is unobstructed by the grab hook and the slab is capable of being lifted and then lowered into final position by the grab hook. The grab hook is so constructed that the minimum space is occupied by the gripping members of the grab hook on each side of the slab, so that the slab may be placed in close proximity to anothersslab,

this being of great advantage when building a double wall with a hollow space, as the gripping members on one side of the slab can be inserted in the hollow space.

A further object is to provide for gripping the material being lifted at a plurality of points on each side to secure greater gr1pping power, and another object is to employ gripping blocks which are flexibly connected to the gripping arms, so that the blocks may conform to the face with which they grip.

Another object is to provide a lever system which will act to contractthe arms bythe downward pull caused by the weight of the material being lifted and to enable the, inst'ant release of the material upon slacking the lifting line. v 7

There are two pairs of arms. The two arms composing each pair being pivoted to each other to swingin one plane and each arm of each pair being also pivoted to the associated arm of the opposite pair, toswing in a plane transverse tothe first mentioned plane, which construction will permit the gripping blocks which restagainst the same face of the material to be adjusted toward or from each other according to the size of the piece of material being lifted, and the second named adjustment permitting the pairs'of blocks to move towardo'r from each other for the clamping-or releasing operations.

Other advantages will be brought out in the following description.

Referringto the drawings: Figure 1 is a perspective view of the complete device. Fig.2 is aside elevation-of the device showing: a slab being lifted by it, dotted lines of the device indicating a releasing position of the arms and dotted lines also indicating adjacent slabs of a hollow wall to which the Slab carried by the device is being fitted. Fig. 3 is a front View of the device, dotted lines showing the arms I of gripping block.

The device comprises two pairs of arms, one pair of arms comprising arms 1 and the other pair comprising arms 2. The arms 1 are pivoted at 3 to the lugs 4 on the upper ends of arms 2, so that the arms 2 may be swung toward or fromthe arms 1. The arms 1 are also pivoted to each other at 5 and the arms 2 are pivoted to each other at 6, the pivots 5 and 6 enabling therespective arms of each pair to be adjusted toward or from each other in a plane transverse to their other movement. Pivoted at 7 to the arms 1 are bell crank levers 8 and one arm 9 of each lever 8 has a plurality of holes 10 to one of which is pivoted the end of a link 11. The link-11 is provided with a series of holes'12 and a pin 13 in each arm2 engages one of the holes 12 of the associated lever 11. The holes 10 permit the inner end of link 11 tobe adjusted toward or from the pivots 7,

of the position of the arms 2 with respect to the arms 1.

Pivot-ally connected to the lower arms of hell crank levers 8 are vertical curved links 14:, which are connected at their upper ends to a yoke 15, the yoke 15 being slidable in a vertical socket 16 which is slotted at 17 for this purpose and which also has slots 18 to receive a pin 19 which projects from the yoke 15 and serves to hold the yoke 15 from transverse movement, while permitting its free Vertical movement in the slots, and also allowing it to'rock. Connected to the yoke 15 above the pin 19 is the lower end of aline 20, which extends down slidably through the upper end of socket 16. The socket 16 has a bracket 21, and the pin 5 is supported therein, this being the pin to which the arms arepivoted.

A rock lever 22 is pivoted by a pin 23 to the lower end of the bracket 21 and the upper end of lever 22 is connected by link 24 with one of the arms 1, while the lower end of the lever 22 is connected by another link 24 with the other arm 1, this connection providing for the adjustment of one set of arms 1 and 2 toward the other set of arms 1 and 2, and insuring that each set of arms 1 and 2 will stand an equal distance with the other set from the center line.

In the lower end of each arm is a tapered hole 25 which receives a pin 26 projecting from a gripping block 27 shown in detail in Figs. 8 and 9. The gripping block is formed with a transverse groove 28, covered with a fabric 29 and with spurs 30 projecting out therefrom. A nut 31 on pin 26 secures the block from transverse movement, while lifting strains are borne by a shoulder 32 on the block which is received in a recess 33 in the a rib 35 on the arm which is received in a corresponding recess in the block. Threaded rods 36 are pivoted at 37 to the arms 1 and detachably engage in slotted lugs 38 with hand nuts 39 for drawing the arms 2 and 1 together to secure extra clamping pressure if desired. When the rods 36 are not used they stand alongside the arms 1, as indicated in dotted lines in Fig. 1.

In use the arms are slipped over the slab, as shown in Fig. 2, and by then lifting on the line 20 the bell cranks 8 will be rocked upon their pivots 7 to draw the links 11 to the left and move the arms 2 toward the arnis 1, thereby clamping the slab bet-ween them with suflicient pressure, so that continued ulling on the line 20 will lift the same. fter the slab is in position the line 20 is slackened which releases the arms 1 and 2 and permits the grab hook to be removed from the slab. In order'to secure the necessary pulling action of the line 20 upon the lever connections, it is obvious that sufficient resistance to upward movement must be afforded by the grab hook, and in most cases this will be sufliciently presented by the weight of the grab hook, together with the engagement of the spurs 30 in the slab to be lifted. After sufficient pressure has been applied, it is obvious that the sliding friction between the slab and gripping blocks will be so great that the weight of the slab itself will supply the necessary resistance to cause the clamping action to take effect. greater clamping pressure between the arms the rods 36 may be swung down to engage the blocks 38 and the nuts 39 may be tightened to draw the arms together, the nuts 39 being loosened after the slab is in position to permit the withdrawal of the grab hook. I

What I claim is:

1. A grab hook comprising two pair of arms, the arms of each pair being pivoted to each other and one arm of each pair being pivoted to the associated arm of the opposite pair, said arms being adapted togrip material between them, a line, and means connected'to said line and to said arms for moving each pair of arms toward the other pair when the line is pulled.

2. A grab hook comprising two pair of arms, the arms of each pair being pivoted to each other and one arm of each pair being pivoted to the associated arm of the opposite pair, said arms being adapted to grip material between them, a line, and means connected to said line and to said arms for moving each pair of arms toward the other pair when the line is pulled, and gripping blocks flexibly connected to the lower ends of the arms for contacting with the article to be lifted.

3. Two pairs of arms, the arms of each pair being pivoted to each other at the top and each arm of each pair being pivoted at the top to the associated arm of the other pair, bell crank levers pivoted to the arms of one pair, links from said bell crank levers to the arms of the other pair, vertically disposed links extending from said bell crank levers upwardly, and a line having connection with said vertically disposed links.

4. Two pairs of arms, the arms of each pair being pivoted to each other at the top and each arm of each pair being pivoted at the top to the associated arm of the other pair, bell crank levers pivoted to the arms of one pair, links from said bell crank levers to the arms of the other pair, vertically disposed links extending from said bell crank levers upwardly, a socket at the upper end of said arms, a yoke slidable in the socket, said vertically disposed links being connected to said yoke, and a line slidable in the socket and connected to said yoke.

'5. Two pairs of arms, the'arms of each pair being pivoted to each other at the top and each arm of each pair being pivoted at the top to the associated arm of the other pair, bell crank levers pivoted to the arms of one pair, links from said bell crank levers If it be necessary to secure a to the arms of the other pair, vertically disposed links extending from said bell crank levers upwardly, a socket at the upper end of said arms, a yoke slidable in the socket, said vertically disposed links being con nected to said yoke, and a line slidable in the socket and connected to said yoke, a pin extending transversely through said yoke, said socket having vertical slots receiving the ends of said pin.

6. Two pairs of arms, the arms of each pair being pivoted to each other at the top and each arm of each pair being pivoted at the top to the associated arm of the other pair, bell crank levers pivoted to the arms of one pair, links from said bell crank levers to the arms of the other pair, vertically disposed links extending from said bell crank levers upwardly, a socket at the upper end of said arms, a yoke slidable in the socket, said vertically disposed links being connected to said yoke, and a line slidable in the socket and connected to said yoke, a bracket supporting said socket and having a pivotal connection with the pivot between the two arms of one pair.

7. A grab hook comprising two pair of arms, the arms of each pair being pivoted to each other and one arm of each pair being pivoted to the associated arm of the oppo site pair, said arms being adapted to grip material between them, a line, and means connected to said line and to said arms for moving each pair of arms toward the other pair when the line is pulled, rods pivoted to the arms of a pair, slotted lugs on the arms of the other pair adapted to receive said rods, and nuts on said rods detachably engaging said slotted lugs.

Copies of this patent may be obtained for 8. A grab hook comprising two pair of arms, the arms of each pair being pivoted'to each other and one arm of each pair being pivoted to the associated arm of the opposite pair, said arms being adapted to grip material between them, a line, and means connected to said line and to said arms for moving each pair of arms toward the other pair when the line is pulled, and means conmeeting the two arms of a pair for causing said arms to be adjusted uniformly from a center line.

9. Two pairs of arms, the arms of each pair being pivoted to each other at the top and each arm of each pair being pivoted at the top to the associated arm of the other pair, bell crank levers pivoted to the arms of one pair, links from said bell crank levers to the arms of the other pair, vertically disposed links extending from said bell crank levers upwardly, a socket at the upper end of said arms, a yoke slidable in the socket, said vertically disposed links being connected to said yoke, and a line slidable in the socket and connected to said yoke, a bracket supporting said socket and having a pivotal connection with the pivot between the two arms of one pair, a lever pivoted to said bracket, a link connecting the top of said lever with one of said arms and a link connecting the bottom of said lever with the other of said arms.

In testimony whereof, I have hereunto set my hand at Los Angeles, California this 9th day of December, 1912.

CHARLES B. HARP.

In presence of- GEORGE T. HAoKLEY, MARY E. BLASDEL.

five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

